tcpdf

When you output a PNG image with transparency via TCPDF, a gray border appears at the junction of the transparency. The original image has no borders How can this be overcome?

I'm using TCPDF to generate some PDFs (obvious) and I need to add a custom font. I took a look at the documentation and it ... all to undefined method TCPDF:: addTTFfont () Is this method addTTFfont somewhere else? How to add custom fonts in TCPDF?